1. Field of the Invention
The present invention relates to a laser treatment apparatus for treating an affected part of a patient by irradiating a laser beam the affected part to be treated with a laser beam.
2. Description of Related Art
There have been known laser treatment apparatus for performing treatments by irradiating an affected part of a patient with a laser beam. In ophthalmic fields, those apparatus are used for photocoagulation treatments to be carried out on the affected part having various fundus diseases such as macular diseases (maculopathy), retinal detachment, etc. and on the peripheral part of the affected part, treatments of aftercataract (secondary cataract) which arises in posterior capsule of crystalline lens, and glaucoma treatments to be carried out by perforating, tapping or incising iris or angle of a patient's eye, and other treatments.
The above-mentioned typical laser treatments need a relatively and accurately specified irradiation spot. An operator therefore has to specify the irradiation spot during his magnification-observation of the patient's eye including the affected part through an observation optical system, and conducts the laser treatments. For the observation optical system, a slit lamp is generally used. In the laser treatments, the observation of the affected part illuminated by an illumination light are often performed in a state where the lightness of the using environment of the apparatus is lowered in order to reduce the influence of interference light from the surroundings of the apparatus, thereby to make easy to observe the interior of the patient's eye.
In the laser treatments, selecting or setting of the optimum parameter of laser beam's wavelengths, output power, and irradiation time, etc. is required according to each treatment's purpose, operational details, and the state of the patient's eye. To enable the operator to easily perform the above selection or settings, there has been known a laser treatment apparatus of a first type in which a control panel is disposed opposite to the operator, namely below eyepieces of the observation optical system. Usually, the control panel is provided with a display part using a light emitting element such as an LED to allow the operator to look set values.
There has been proposed a laser treatment apparatus of a second type that is provided with a control panel separately structured from the apparatus body, in which various information needed for treatments or observation of a patient's eye is displayed in a visual field of a finder of the slit lamp. The information is displayed optically or mechanically in the form of characters or numerals within the visual field viewed through the finder.
However, concerning the first type of the apparatus, when the environment's lightness is lowered to start laser treatment, operator's eyes receive the light from below because the display part of the control panel disposed directly below the eyepieces of the observation optical system is too bright with respect to the darkness of the using environment. Thus, the patient's eye including the affected part is not well observed by the operator due to the light from below. The operator, receiving such the dazzling light from below, can not concentrate his attention on the treatment operation, and needs a long time for alignment to specify the part to be treated. This may impose a burden on the patient's eye.
Furthermore, in using the apparatus of the first type, the operator must detach his eyes from the eyepieces of the slit lamp finder and look the settings displayed on the control panel to confirm as to whether or not the condition of the treatment laser beam is set in correspondence to the purpose of treatment to be carried out. Such the confirmation by the detachment of operator's eyes from the finder every time before the laser irradiation is troublesome for the operator. Meanwhile, the patient is kept waiting. The operator can not also concentrate his attention on the observation of the affected part of the patient's eye. If the operator does not detach his eyes from the finder during the laser treatment, he can not confirm whether the set condition of the treatment laser beam answers the treatment purpose.
In the case of the apparatus of the second type, the information is displayed at the constant brightness level within the visual field of the finder. According to the brightness of the observation visual field, which varies with the observed region of the patient's eye and the illumination light quantity, therefore, the observed region and the displayed information are hard to view. Specifically, the bright observation visual field causes difficulty in discriminating the displayed information, while the dark visual field gives a feeling of glaring to the operator's eyes and causes difficulty in viewing the observed region.